Azo dyestuffs and a process of making same



Patented May 27, 1952 AZO DYESTUFFS AND A PROCESS OF MAKING SAMIE Ernst Iselin and Walter Wehrli, Basel, Switzerland, assignors to Sandoz Limited, Basel, Switzerland, a Swiss firm N Drawing. Application July 13, 1949, Serial No. 104,588. In Switzerland July 16, 1948 13 Claims.

It is known that azines can be obtained from ortho-aryl-aminoazo compounds by treatment with acids (see e. g. Fierz-David Ktinstliche organische Farbstoffe, Berlin 1926, page 309). In a similar manner hydroxyazine-sulfonic acids can be prepared which are capable of coupling with diazo compounds to form azo dyestuffs (see U. S. Patent No. 1,877,743).

It has now been found that azo dyestuffs containing the azine ring can also be obtained when azo dyestuffs of the formula OH NH aryl R- azo azo-R' wherein the naphthalene residue must contain at least one sulfonic acid group united to the nucleus and in which aryl denotes a substituted or unsubstituted benzene or naphthalene residue containing at least one free position ortho to the imino group, R-azo and R-azo are any desired residues of diazo compounds containing if desired further azo linkages and in which both R-azo and OH as well as R'-azo and NH-aryl are in the ortho-position to one another and treated with acids or acid salts, while warming if desired.

Compared to the known methods for the preparation of azo dyestufis containing the azine ring, the new process offers a method whereby the azine ring formation is completed at the last stage in the process which is an appreciable advantage. Whereas the known hydroxynaphthophenazine-sulfonic acids or hydroxydinaphthazine-sulfonic acids used for coupling possess only a slight coupling energy, the azo dyestuffs obtainable from arylamino-hydroxynaphthalene sulfonic acids by acid coupling in the orthoposition to the NH-aryl group, couple smoothly 2 and can also be combined with diazo compounds which only couple with slight energy and which therefore react with the above named azines onl incompletely or not at all.

The conversion of the disor polyazo-dyestufis used according 'to the process into the dyestufis containing the azine ring can take place either in aqueous solution by warming with acids or acid salts or by introducing the dyestufis into concentrated acids at room temperature, if desired with cooling.

As acids there can be used for instance: hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, methane sulfonic acid, benzene monoand disul-fonic acid and naphthalene mono-, diand trisulfonic acid. As acid salts there can be used for instance alkaline metal bisulfates, primary alkaline metal phosphates and acid alkaline metal oxalates.

Disand polyazo dyestuffs which are suitable for azine ring closure according to the present process can for example be obtained from the following arylaminohydroxynaphthalene sulfonic acids: 2-arylamino 5 hydroxynaphthalene-lsulfonic acid, 1-arylamino-8-hydroxynaphthalene-4-sulfonic acid, l-arylamino 8 hydroxynaphthalene-4.6-disu1fonic acid, l-arylamino-lhydroxynaphthalenei-sulfonic acid.

The dyestuffs which can be obtained according to the present process in those cases where they contain groups capable of forming metal complexes can be converted in the usual manner into the metal complex by treating them with metal salts, e. g. copper, chrome, cobalt, nickel, iron and manganese salts. Most of these metal complex compounds possess outstanding fastness properties.

The following examples which are given by way of showing how the invention may be carried out in practice are non-limitative. The parts are by weight.

Example 1 HOalS (])E Q 1110 mNOs 03H z HOaS- 23.4 parts of l-nitro-2-aminophenol-6-sulfonic acid were diazotised in the usual way and coupled in the presence of soda while cooling with ice with 54.3 parts of the sodium salt of the nonoazo dyestuif obtained by coupling diazotised sulfanilic acid with 2phenylamino-5-hydroxynaphthalene-7-sulfonic acid in an acid medium. For facilitating the coupling 5-10% by volume of pyridine bases may be added. After coupling is finished the diazo dyestuff is isolated. It dissolves in water with a red colour and in concentrated sulfuric acid with a blue-green colour.

In order to close the azine ring the disazo dyestufi is dissolved in 1400 parts of hot water and treated at 85-90 C. with 110 parts of 30% hydrochloric acid. It is stirred for 2 hours at 85-90 (3., then made alkaline and isolated as usual. The dyestufi dissolves in water with a blue-grey colour and in concentrated sulfuric acid with a green colour; wool is dyed from acid baths in brownish-red shades and by, after-chrcming in dark olive shades ofnoteworthy fastness properties. The dyestufi is identical with that obtained by alkaline coupling of diazctised -Ilitl'O- 2-aminophenol-6-sulfonic acid with 5-hydroxy- 1.2-naphthophenazine-'T-sulfonic acid in the presence of pyridine bases with noticeably smaller yields of the dyestufi. The sulfanilic acid obtained in the ring closure can be used again for further batches.

Ifin this example there is used instead of the azo dyestufi obtained by acid coupling of diazotised 'sulf a'nilic. acid with Z-phenylarnino-E-hydroXynaphthalene-7-sulfonic acid the corresponding dyestuff from Z-phenylamino-S-hydrox'y-iia'phthalene-T-sulfonic acid and diazotised'aniline, diazotised orthanilic or nietanilic acid, then the same azine dyestufi is obtained. Instead of. hydrochloric acid there can be used with the same effect hydrobromic acid, sulfuric acid or phosphoric acid.

17.8 parts of 4.6-dichlor-2-aminophenol are diazotised in the usual manner and coupled with ice cooling in the presence of sodium carbonate with 64.5 parts of the sodium salt of the monoazo dyestufi obtained by the acid coupling of diazotised l-amino-benzene-2.5-disulfonic acid with 2 phenylamino 5 hydroxynaphthalene 7 sulfonic acid. 540% by volume of pyridine can be added to facilitate the coupling. The dyestufi thus obtained dissolves in hot water with a dark bluish-red colour and in concentrated sulfuric acid with a dark green colour. In order to close the azine ring it is added at 40 C. to 650 parts of concentrated sulfuric acid, stirred for 2 hours at 40 C., poured into ice and water and isolated. The azine dyestuff is a dark powder which dissolves in hot water with a blue colour and in concentrated sulfuric acid with a green colour. Wool is dyed from acid baths in brown shades and by after-chroming in grey shades with noteworthy fastness properties. This dyestuff cannot be prepared by coupling diazotised 4.6-dichlor-2-aminophenol with S-hydroxy-LZ- naphthophenazine-7-sulfonic acid as the coupling energy both of the diazo compound and of the azine is too small.

In place of the monoazo dyestuff from diazotised l-aminobenzene-2.5-disulfonic acid and 2- phenylan lino 5 hydroxynaphthalene 7 slulionic acid the coupling products from diazotised e-chloraniline-2-sulfonic acid, l-naphthylamin'o- 4-sulfonic acid or 2-naphthylamino-4'B-disulfonic acid with 2 phenylamino 5 hydroxynaphthalene-l-sulfonic acid can be used with similar results. The final dyestufi is in all cases the same.

If instead of 2 phenylamino 5 hydroxynaphthalene 7 sulfonic acid, there is used 2 (4' hydroxy 5' carboxy) phenylamino- 5-hydroxynaphthalene-7-sulionic acid for the preparation of the acid coupled monoazo dyestufi, then there is obtained afinal dyestufi of similar shades and similar fastness properties. Instead of sulfuric acidthere can be used with the same effect organic acids, as for instance formic acid, acetic acid or oxalic acid.

lee

14.4 parts of 4-chlor-2-aminophenol arediazotised as usual and'coupled in the presence of sodium carbonate to render alkaline with ice cooling and, if desired, with the addition of 540% by volume of pyridine, with 55.7 parts of the sodium salt of the monoazo dyestufi' obtained by acid coupling of diazotised 2-toluidine-4-sulfonic acid with 1 phenylamino 8 hydroxynaphthalenel-sulfonic acid. Thereupon the product of the coupling is added to 650 parts of concentrated sulfuric acid at 40 C. and stirred for 2 hours at 40 C. When poured into ice and water and filtered, the dyestufi forms a red powder which dissolves in water with a red colour and in concentrated sulfuric acid with a blue-black colour. Wool is dyed red-brown from an acid bath and is dyed grey by after-chroming,

whereby dyeings of good fastness properties are If, instead of 38.4 parts of l-hydroxynaphthaobtained. lene-3:6:8-trisulfonic acid, 30.4 parts of 1-hy- This dyestuff is not obtainable by coupling droxynaphthalene 3:8-disulfonic acid or 30.4 diazotised 4-chlor-2-aminophenol with B-hyparts of 1-hydroxynaphthalene-3:6-disulfonic droxy-1.2-naphthophenazine-4-sulfonic acid as 5 acid or 32.0 parts of 1:B-dihydroxynaphthalenethe latter will not couple with diazotised 4-chlor- 3:6-disulfonic acid are used, there will be ob- 2-aminophenol. Instead of sulfuric acid there tained dyestufis of similar shades and fastness can be used acid salts as for instance alkaline properties. metal bisulfates, primary alkaline metal phosphates or acid alkaline metal oxalates. Example 5 Example 4 24.4 parts of dianisidine are tetrazotized in the conventional way and combined with 30.4

24.4 parts of dianisidine are tetrazotised as parts of l'hydloxynaphthalene'3is'disummm usual and coupled in the presence f soda and acid in the presence of sodium carbonate and t ice cooling t 3 4 parts of 1 While cooling with ice. After formation of the innaphtha1ene 3 6 8 trisu1phOnic acid After termediate product an alkaline solution of the mation of the intermediate compound has en- Sodlum Salt of Parts of the monoazo sued an alkaline solution of 54.3 parts of the 813111? f e d by acid coupling diazotized sulsodium salt of the monoazo dyestuif obtained by fenllle acld Wlth y y-7:7-disulfo-2:2'- acid coupling of diazotised sulfanilic acid with dmaphthylamine is addedhe c plin per 2 phenylamino 5 hydroxynaphthalene 7 tion being completed the dyestuff of the formula HO3IS on OCH; ([1053 11 11 SO:4H lIOiS NH- soar! N=NOS 03H sulfonic acid is added. After the coupling is is isolated and dissolves then in hot water with finished the dyestuif of the formula a blue coloration.

BOaS OH 00113 OCHa OH HOaS- -s 03H HOaS- NH is isolated; this dissolves in hot water with a blue colour and in concentrated sulfuric acid with a greenish-blue colour. For converting the trisazo dyestufi into the dye- For conversion into the dyestuff containing the stuff containing the azine ring the former is disazine ring the trisazo dyestufi is dissolved hot in solved hot in 1200 parts of water, whereupon at 1000 parts of water, 67 parts of 30% hydroatemperature of 85-90 C. 50 parts of 30% hydrochloric acid added at 85-90 C., and the product chloric acid are added and the whole stirred at stirred for 1 hour at this temperature. When the this temperature for one hour. After formation azine formation is finished the solution is made of the azine structure the solution is made alkaalkaline and the dyestuff isolated. It is soluble line and the dyestuff isolated, whereupon it is in hot water with a greenish-blue colour and in soluble in water with a greenish blue color and concentrated sulfuric acid with a green colour in concentrated sulfuric acid with a blue green and can be converted into a copper complex by The fi" can be Converted into & C D- the usual processes. This complex dyes cotton per complex according to conventional methods. and regenerated cellulose in bright greenish-blue The same dy Cotton d e e ated ce lulose shades of excellent fastness to light and to in vivid greenish blue shades of excellent fastwashing. ness properties to light and to washing.

A copper complex having even brighter dyeing When using, instead of 30.4 parts of l-hydroxyproperties with very similar shades is obtained by naphthalene-3 :8-disulfonic acid, thesame quanthe use of acid monoazo dyestuifs obtained from tity of 1-hydroXynaphthalene-3:fi-disulfonic acid 2 p anisidylamino 5 hydroxynaphthaleneor 32.0 parts of '1:S-dihydroxy-naphthalene-3:6- '7-sulfom'c acid. Instead of hydrochloric acid disulfonic acid or 38.4 parts of l-hydroxynaphthere can be used with the same effect organic thalene-S26:8-trisulfonic acid and working otheracids as for instance methane sulfonic acid, ben- Wisein the same manner as indicated above, dyezene monoand disulfonic acids or naphthalene stuffs willbe produced which'give similar shades.

mono-, diand trisulfonic acids. and possess analogous properties.

Example 6 The aminodisazo dyestufi" (which is obtained from 15.3 parts of the -aminosalicylic acid) of the formula is dissolved in hot water, treated with common salt and? partsof: sodium nitrite andaiter cooling to 0 C. added to adjpartsiof hydrochloric acid and ice. Whenthe diazotizationzis finished the: dia-zo compound is filtered ofi stirred with1ice-water and coupled inlthepresenceoi sodium carbonate with ice cooling with; 54.3 parts. of thezsodiumi salt. of the monoazol dyestufii obtained: bytheacid: coupling of. diazotisedl sulphanilic acid: withipheny1amino-. 5- hydroxynaphthalenee'lsulfonic acid.

66' parts; of the.tetrakisa-zo: dyestufif so obtained:

HOsS

are: then addedrwithaice=coolingi to 600. parts of 75 concentrated sulfuric acid and stirred for 2 hours at 5 C; The solution is then poured onto ice and water and the dyestuff worked up in the usual manner. It dissolves in hot Water with a violet colour and in concentrated sulfuric acid with a blue colour and dyes cotton and regenerated cellulose in reddish-blue-grey shades of good fastness to light and to washing, which are still further improved by after-treatment with copper yielding agents.

Example 7 I L L OOH MD N to stirred at room temperature in concentrated sulfuric acid, and after 2 hours stirring the azine body is separated. It forms a brown powder which dissolves in hot water with a brown colour and in concentrated sulfuric acid with a blackbrown colour. Cotton and regenerated cellulose are dyed in brown shades. By after-treatment of the fibres with copper yielding agents the fastness is improved without the shade of the dyeing being appreciably altered.

Example 8 OGHa excellent fastness properties to light and to wash- .ing when after-treated with copper yielding agents.

The dyestuff may be converted into a copper complex by the usual methods. This complex dyes cotton and regenerated cellulose in greenishgrey shades of outstanding fastness to light and to washing.

Example 9 17.8 parts of 4.6-dichlor-2-aminophenol are The aminoazo dyestufi" of the formula:

(I)CHa H O O (E Ha are added to 800 parts of concentrated sulfuric acid at 20-30 C. and stirred for 2 hours at 2030 C. The mixture is then poured into a mixture of ice and water and the dyestufi worked up according to known methods. It dissolves in hot water with a violet shade and dyes cotton and regencrate-d cellulose in bluish-grey shades showing HOaS- diazotised in the usual manner and coupled with ice cooling in the presence of sodium carbonate With 64.5 parts of the monoazo dyestufi obtained by the acid coupling of diazotised l-amino-benzene-disulfonic acid with 2- (2'-naphthylamino)- 5-hydroxynaphthalene-'7-sulfonic acid. 5-10 per cent by volume of pyridine can be added to facilitate the coupling operation. The dyestuff thus obtained dissolves in hot water with a dark bluishred colour and in concentrated sulphuric acid with a dark green colour. In order to close the azine ring it is added at 40 C. to 650 parts of com centrated sulfuric acid, stirred for 2 hours at 40 C., poured into ice and water and isolated; the azine dyestuff is a dark powder which dissolves in hot water with a blue colour and in concentrated sulfuric acid with a green colour. Wool is dyed from acid baths in brown shades and by afterchroming in grey shades with noteworthy fastness properties.

The following list shows further examples of dyestuffs obtained according to the process.

Copper complex ofiig OH H(]) (IJH blue-grey HOaS N=NN=N N=N- H 0 3S- so H Copper complex of- HOaS OH HOOC COOH Dyeings on cotton What we claim is:

l. A process for the manufacture of an azo dyestufi containing the azine ring, comprising the step of subjecting an azo dyestuff which corresponds to the formula wherein the naphthalene radical contains at least one nuclearly linked SOaH group, aryl stands for a radical containing at least one free o-position to the NH group and is selected from the class consisting of mononuclear radicals of the benzene series and binuclear radicals of the naphthalene series, and R stands for a radical selected from the class consisting of mononuclear radicals of the benzene series and binuclear radicals of the naphthalene series, and X stands for a radical containing at least one azo group, each lastnamed azo group being connected within the radical X to a member selected from the class consisting of mononuclear radicals of the benzene series, binuclear radicals of the naphthalene series and binuclear radicals of the diphenyl series, and wherein X is in o-position to the OH group and azoR is in o-position to the NH-aryl group, to the action of an agent selected from the class consisting of acids and acid salts, until the corresponding azine ring-containing azo dyestufi is produced.

2. A process for the manufacture of azo dyestuff containing the azine ring, comprising the step of subjecting an azo dyestuff which corresponds to the formula HO NH-aryl R-azo azo-18,

wherein the naphthalene radical contains at least one nuclearly linked SOaH group, aryl stands for a mononuclear radical of the benzene series containing at least one free o-position to the NH group, and each of R and R stands for a mononuclear radical of the benzene series, and wherein R-azo is in o-position to the OH group and azo-R is in o-position to the NH-aryl group to the action of a mineral acid until the corresponding azine ringcontaining azo dyestuff is produced.

3. A process for the manufacture of an azo dyestufi containing the azine ring, comprising the step of subjecting an azo dyestufi which corresponds to the formula HO NBC-aryl R azo-Razo azoR;

wherein the naphthalene radical contains at least one nuclearly linked SOaH group, aryl stands for a mononuclear radical of the benzene series containing at least one free o-position to the NH group, and each of R, R and R1 stands for a mononuclear radicalof the benzene series, and wherein Ri-azo-R-azo is in o-position to the OH group and azo-R is in o-position to the NI-I-aryl group to the action of a mineral acid until the corresponding azine ring-containing azo dyestufl, is produced.

4. A process for the manufacture of an azo dyestufi containing the azine ring, comprising the step of heating with a mineral acid an azo dyestuff which corresponds to the formula H 0 N H-aryl wherein the naphthalene radical contains at least one nuclearly linked SOaH group, aryl stands for a mononuclear radical of the benzene series containing at least one free o-position to the NH- to the action of a mineral acid until the corresponding azine ring-containing azo dyestufi is produced.

6. Aprocess for the manufacture of an azo dyestufi containing the azine ring, which comprises the step of subjecting the azo dyestufi of 40 the formula H O aS O H O C H 0 G H3 1 l 1 HOaS-- SO3H H038- to the action of a mineral acid until the corre sponding azine ring-containing azo dyestufi is produced.

7. A pr cess fer the manufacture of an azo dyestufi containing the azine ring, which comprises the step of subjecting the azo dyestuff of the formula to the action of a mineral acid until the corresponding azine ring-containing azo dyestufi is produced.

3. A process for the manufacture of an azo dyestuff containing the azine ring, which com- 16 prises the step of subjecting the azo dyestufi of the formula to the action of a mineral acid until the corresponding azine ring-containing azo dyestuff is produced.

9. An azo dyestuff of the formula SOaH wherein the naphthalene radical contains at least one nuclearly linked SOaI-I group,

is a portion of a member selected from the group consisting of radicals of the benzene and naphthalene series, and X stands for a radical containing at least one azo group, each said azo group being connected within the radical X to a member selected from the group consisting of radicals of the benzene and naphthalene series, and

wherein both N-atoms are in o-position to each other with respect to the naphthalene radical, and X is in o-position to the OH group.

17 18 10. An azo dyestufi of the formula zene series, and each of R2, R1 and R stands for N a mononuclear radical of the benzene series, and H wherein both N-atoms are in oposition to each 0 other with respect to the naphthalene radical, and 5 Rz-azo-Rrazo-R-azois in o-position to the OH group. R R l 0 12. The azo dyestufi of the formula l-ezo azo \N/ (30H; ()H wherein the naphthalene radical contains at least one nuclearly linked SOaH group, L

\ H0041 (3H1 H038- C I v is a portion of a mononuclear radical of the benzene series, and each of R1 and R stands for a mononuclear radical of the benzene series, and wherein both N-atoms are in o-position to each other with respect to the naphthalene radical, 13. The azo dyestuff of the formula on HO-N= -N=N N=N- HOO(JJ Hois- S OaH /N N I O and R1-azo-R-azo is in o-pcsition to the OH ERNST ISELIN. group. WALTER WEHRLI.

11. An azo dyestufi of the formula HO N REFERENCES CITED The following references are of record in the I E file of this patent:

UNITED STATES PATENTS Rz-GZOR19.Z0-R-8ZO r/ Number Name Date wherein the naphthalene radical contains at least 1,377,743 stlzaub t a1 Sept. 13, 1932 one nuclearly linked 5031-! group, 2,435,356 Kalsel: 1948 2,529,527 Wehrh et a1 Nov. 14, 1950 is a portion of a mononuclear radical of the ben- 

12. THE AZO DYESTUFF OF THE FORMULA 